Bodge
Posts: 458
Joined: 2/14/2004
From: Northampton, UNITED KINGDOM
Status: offline
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Gyroscopic procession will have most effect at high revs during tight manouvres or direction changes. The changes in angular velocity (revs may not change, but velocity does) during these turns is subject to conservation of energy laws, i.e. any changes have to be made up elsewhere in the system to maintain equilibrium. These forces act through the bearings to try and make the plane twist. This is not torque reaction.
On radial saws the bearings are supporting linear cutting forces not gyroscopic since the rotation axis is not changing: in a model engine the gyroscopic procession applies the load of a changing fraction of the prop mass to the bearings - not greatly significant.
The firing forces applied by the rod will apply a greater load on the bearings than gyroscopic forces. With a heavy prop the firing forces are working against the inertia and aerodynamic resistance of the prop so the load will be higher anyway because of the larger more massive prop. Clearly gyroscopic forces will be greater here, but will still only be some fraction of the prop's weight
In short - gyroscopic forces are a minor component in the system of forces acting through model engine bearings. In fact model engine bearings (ignoring corrosion) have quite an easy life assuming you are not smacking the deck with the prop too often.
Mick.
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gyroscopic progression - 
